A better way to print formatted floats using the `format()` specs.

float_formating.py

def float_spec(fill, align, sign, width, separator, precision):

    if len(fill) > 1:
        raise ValueError('The fill character can only contain 1 character.')

    if align not in ['left', 'right', 'center', 'padded']:
        raise ValueError('{} is not an allowed alignment.'.format(align))

    if sign not in ['+', '-', ' ']:
        raise ValueError('{} is not a valid sign.'.format(sign))

    if width < 0:
        raise ValueError('Width must be 0 or greater.')

    if precision < 0:
        raise ValueError('Precision must be 0 or greater.')

    # if there will be no padding, width=0, omit fill, align, and width from
    # the generated format spec.
    if width == 0:
        fill = ''
        align = 'blank'
        width = ''

    align_spec = {
        'left': '<',
        'right': '>',
        'center': '^',
        'padded': '=',
        'blank': ''
    }

    separator = ',' if separator is True else ''

    return '{{:{0}{1}{2}{3}{4}.{5}f}}'.format(
        fill,
        align_spec[align],
        sign,
        width,
        separator,
        precision
    )
    
    
def pretty_float(x, precision, width, fill, align, sign, separator):
    out = float_spec(fill, align, sign, width, separator, precision)
    return out.format(x)
    
    
def float_ljust(x, precision, width, fill=' ', separator=True, sign=' '):
    return pretty_float(x, precision, width, fill, align='left', sign=sign,
                        separator=separator)


def float_rjust(x, precision, width, fill=' ', separator=True, sign=' '):
    return pretty_float(x, precision, width, fill, align='right', sign=sign,
                        separator=separator)


def float_center(x, precision, width, fill=' ', separator=True, sign=' '):
    return pretty_float(x, precision, width, fill, align='center', sign=sign,
                        separator=separator)


def float_padded(x, precision, width, fill=' ', separator=True, sign=' '):
    return pretty_float(x, precision, width, fill, align='padded', sign=sign,
                        separator=separator)